1. Field of the Invention
The present invention relates to a mobile communication terminal and, more particularly, to mobile communication terminal which is capable of transmitting and receiving non-voice data during a voice call.
2. Background of the Invention
Generally, a mobile communication terminal is a portable device which performs wireless communication. Wireless communication is typically performed by communicating with a base station in a service area, which is connected to a mobile switching center (MSC) that switches traffic. A conventional mobile communication terminal can perform voice communication, data communication (e.g., communication of symbols, numbers and characters) and/or multimedia communication (e.g., communication of images). Some recently developed mobile communication terminals include a camera, and have the capability of transmitting video in real time.
A conventional method of performing voice communication is described below.
The method begins by a mobile communication terminal receiving voice signals from a user through a microphone of the mobile communication terminal, and outputting the voice signals to an audio codec in the mobile communication terminal. Alternatively, previously stored voice signals may be outputted to the audio codec.
The audio codec then converts the voice signals to digital signals, codes the digital signals using pulse code modulation (PCM), and outputs the coded signals to a vocoder of a central processing unit (CPU) for processing. An output of the vocoder is then transmitted to a recipient mobile communication terminal.
When the recipient mobile communication terminal receives the transmission signals, they are processed by a vocoder of the recipient mobile communication terminal. The vocoder then outputs signals to an audio codec of the recipient mobile communication terminal.
The audio codec performs PCM decoding on the signals output by the vocoder, and converts the decoded signals into analog voice signals. The analog voice signals are then output through a speaker of the recipient mobile communication terminal.
One shortcoming of the conventional mobile communication terminal described above is that, during a voice call, the mobile communication terminal is not capable of transmitting or receiving data other than voice signals (such as, for example, image data or text data).